Aim 1. We created an outbred population of flies from the five longest-sleeping and five shortest-sleeping DGRP lines. We first performed a full diallel cross of these lines. We then randomly mated flies from the F1 generation of this cross to create the first generation of outbred flies. We continued the random mating procedure for 13 generations, allowing SNPs from the long and short-sleeping flies to recombine. We chose 96 representative SNPs from the genome-wide association study that segregate in the outbred population and developed Taqman assays for each SNP. Aim 2. From the outbred population, we will create three selection populations. One population will be selected for short sleep, one for long sleep, and we will maintain an unselected control. We will measure sleep in each selection population and the control every generation. We will choose a subset of flies to create the subsequent generation as appropriate (for example, the shortest-sleeping flies from the population selected for short sleep will be used as parents for the next generation). We will plot the overall mean sleep for each selection population relative to the control selection population in order to ascertain the effectiveness of the selection procedure. We will use high-throughput genotyping methods to genotype flies at various generations during the selection procedure. We will first determine SNP allele frequencies in the outbred population prior to selection, then measure the allele frequencies of SNPs in the selection populations at five subsequent generations. We will associate SNP genotypes with the sleep phenotypes we measure in the selection populations for each generation. Significant SNPs denote genomic regions responsive to the selection procedure.